Applications of DFT to the Theory of Twentieth-Century Harmony Jason Yust Boston University, 855 Comm. Ave., Boston, Mass., 02215, United States
[email protected] http://people.bu.edu/jyust Abstract. Music theorists have only recently, following groundbreaking work by Quinn, recognized the potential for the DFT on pcsets, initially proposed by Lewin, to serve as the foundation of a theory of harmony for the twentieth century. This paper investigates pcset \arithmetic" { subset structure, transpositional combination, and interval content { through the lens of the DFT. It discusses relationships between inter- val classes and DFT magnitudes, considers special properties of dyads, pcset products, and generated collections, and suggest methods of us- ing the DFT in analysis, including interpreting DFT magnitudes, using phase spaces to understand subset structure, and interpreting the DFT of Lewin's interval function. Webern's op. 5/4 and Bartok's String Quartet 4, iv, are discussed. Keywords: Discrete Fourier transform, pitch-class set theory, twentieth- century harmony, posttonal theory, Webern, Bartok, generated sets 1 Introduction In American music theory of the 1960s and 1970s, the era of Allen Forte's am- bitiously titled book The Structure of Atonal Music [12], a theory of harmony for the twentieth century seemed not only a possible but a natural goal of the discipline. In latter years, the idea of pursuing a general theory for such an eclec- tic century would come to seem increasingly audacious. But recent advances in mathematical music theory should reignite this enterprise: in particular the ap- plication of the Fourier transform to pcsets [3, 5, 9, 15, 18, 19].